Catalytic muffler

ABSTRACT

A POLLUTION REDUCING MUFFLER FOR INTERNAL COMBUSTION ENGINES IN WHICH EXHAUST GASES, AFTER ENTRY INTO THE MUFFLER HOUSING, ARE DISTRIBUTED FOR PASSAGE THROUGH A PLURALITY OF LONGITUDINAL CONDUITS, EACH OF WHICH CONTAINS A SERIES OF COILS OF STAINLESS STEEL WIRE THROUGH WHICH THE EXHAUST GASES MUST PASS. AN AIR CONDUIT, WHICH EXTENDS LONGITUDINALLY THROUGH THE MUFFLER, RECEIVES ATMOSPHERIC AIR FROM THE EXTERIOR OF THE MUFFLER HOUSING. THIS AIR IS HEATED IN ITS PASSAGE THROUGH THE AIR CONDUIT AND IS MIXED WITH THE GASES PASSED THROUGH THE EXHAUST CONDUITS PRIOR TO DISCHARGE FROM THE MUFFLER HOUSING. THE AIR CONDUIT IS PREFERABLY PROVIDED WITH INTERIOR BAFFLLES TO DEFINE A SERPETINE FLOW PATH THROUGH THE CONDUIT TO PROLONGL THE RESIDENCE OF THE AIR WITHIN THE CONDUIT TO FACILITATE HEATING OF THE AIR.

Jan. 30, 1973 F. J. GREIPEL CATALYTIC MUFFLER Filed Aug. 9. 1971 L J a R mm 3 NR 4 m6 3 IJ. y K N j Z 3 M El z m;

ATTORNEYS United States Patent 3,713,783 CATALYTW MUFFLER Frank J. Greipel, 49 E. Larpenteur Ave., St. Paul, Minn. 55117 Filed Aug. 9, 1971, Ser. No. 170,220 Int. Cl. litltj 9/04; Ftlln 1/14, 3/16 US. Cl. 2328& F 8 Claims ABSTRACT OF THE DISCLOSURE A pollution reducing mufiler for internal combustion engines in which exhaust gases, after entry into the muflier housing, are distributed for passage through a plurality of longitudinal conduits, each of which contains a series of coils of stainless steel wire through which the exhaust gases must pass. An air conduit, which extends longitudinally through the muffler, receives atmospheric air from the exterior of the mufller housing. This air is heated in its passage through the air conduit and is mixed with the gases passed through the exhaust conduits prior to discharge from the mufiler housing. The air conduit is preferably provided with interior baflles to define a serpentine fiow path through the conduit to prolong the residence of the air within the conduit to facilitate heating of the air.

This invention relates to a mufller for attachment to the exhaust manifold of an automotive engine or similar internal combustion engine for the purpose of reducing objectionable constituents, such as unburned hydrocarbons and carbon monoxide, emitted from the exhaust system of the engine.

The exhaust gases from the average automobile and smiilar internal combustion engine contain a mixture of carbon monoxide, carbon dioxide, unburned or partially burned hydrocarbons, nitrogen, some of the nitrogen oxides, etc. These exhaust gases contribute to the production of smog and similar forms of air pollution in such quantities as to be considered objectionable and potentially harmful. The Federal Government and the States, led by California, are legislating increasingly stringent requirements for control of emissions from automobile engines.

Great difficulty has been encountered in the production of an anti-pollution muffier which is not only effective but capable of production in large quantities at a reasonable price for use both as original equipment and for replacement of existing automobile mufiiers. The present invention is directed to a relatively simple mufller system for exhaust gases from internal combustion engines to effectively reduce the content of objectionable gaseous constituents, as well as to reduce noise, which is capable of relatively economical manufacture.

The invention is illustrated by the accompanying drawings in which the same numerals refer to corresponding parts and in which:

FIG. 1 is a plan view in section of a muffler according to the present invention;

FIG. 2 is a front end elevation thereof;

FIG. 3 is a transverse section on the line 22 of FIG. 1 and in the direction of the arrows; and

FIG. 4- is a plan view partly broken away and partly in section to better show interior construction.

Referring now to the drawings, the muffler according to the present invention includes an elongated tubular housing, indicated generally at 10, of generally oval cross section, constructed of heat resistant sheet metal. The housing has a front end plate or cap 11 having an inlet 12 of reduced diameter for receiving obnoxious exhaust gases from an internal combustion engine and an end plate or cap 13 having a similar outlet 14 of reduced diameter at the opposite end of the housing for discharge of purified exhaust gases.

Disposed in the housing 10 immediately adjacent to end plate or cap 11 and in communication with inlet 12, there is an exhaust receiving and distributing chamber 15. A similar air and exhaust mixing discharge chamber 16 is disposed at the downstream end of the housing immediately adjacent to end plate or cap 13 in communication with discharge outlet 14.

An air conduit 17 extends through the upstream end plate 11 along the length of the housing 10 adjacent one side thereof to the downstream mixing chamber 16. Conduit 17 is rectangular in cross section and is open at both ends. Being open at the upstream end, when the mufiier is horizontally disposed as intended, air is scooped into the conduit with forward motion of the vehicle of which the mufller is a part.

A plurality of baffles 18 and 19, which are desirably flanged as shown, are provided within air conduit 17 to retard the flow of air through the conduit. The bafiles 18 and 19 are disposed angularly downstream extending from the opposite side walls of the conduit to or slightly past the center line thereof in spaced apart alternate staggered relation so as to provide a serpentine flow path through the conduit. The angular disposition of the baffle plates facilitates downstream passage of air through the conduit while the baffle plates, especially if flanged, inhibit back flow.

For ease of assembly, the bafile plates 18 and 19 are desirably welded or otherwise secured to a central rod 20, which is preferably of rectangular cross section. The plate and rod assembly fits with a close slide fit within the conduit 17 and can be secured therein by welding the end most baffle plates, for example.

A plurality of exhaust conduits or ducts 21, 22 and 23 of similar size and structure are disposed in the housing between chambers 15 and 16. The exhaust conduits are likewise of rectangular cross section and are desirably disposed in a cluster of abutting elements as shown with conduit 21 disposed on top of conduit 22 and conduit 23 disposed to one side of them in general alignment with air conduit 17. The combined height and width of the cluster of conduits approximates the inside dimensions of housing 10, leaving four channels or passages 24 defined in the spaces between the housing wall and the walls of the adjacent pairs of conduits.

The air conduit 17 and exhaust conduits 21-23 are formed from thin stainless steel tubing, preferably of square cross section. Baflie plates 18 and 19 and rod 20 are likewise preferably formed from stainless steel.

The flow of exhaust gases through conduits 21-23 is obstructed to some extent by the disposition of a plurality of coils 25 of stainless steel wire. The stainless steel wire coils 25 are of an outside diameter and length approximating the inside dimensions of the tubing forming the exhaust conduits and the coils are disposed in side-byside relation with their axes extending transversely relative to the longitudinal axes of the conduits. Although shown with the axes of all coils parallel to one another, the identical effect is achieved if the axes of some of the coils are disposed perpendicular to those of other coils.

The coils are desirably formed from Wire between about 14 gauge and 24 gauge (American or B & S Standard) and are coiled in a relatively loose coil. For example, using 18 gauge stainless steel wire, a coil 2 inches in diameter has about 35 turns in its 2 inch length. The ends of the exhaust conduits are closed by and adjacent coils are separated by relatively coarse mesh stiffrigid screening 26, formed, for example, from expanded stainless steel sheeting and desirably flanged, as shown.

Desirably, as shown in FIG. 4, the passages 24 are obstructed by bafiles 27 disposed transversely within the passages, desirably spaced about one-third the length of the exhaust conduits measured from the inlet end. Immediately upstream from the baffles 27, a plurality of holes 28 pass through the side walls of exhaust conduits 21 and 22 and the top and bottom walls of conduit 23 so that any exhaust gases passing through passages 24 are diverted into the exhaust conduits.

In its passage through air conduit 17, atmospheric air is super-heated by the hot exhaust gases passing through the adjacent exhaust conduits 21 and 22 and passages 24. Stainless steel is known to have a catalytic effect in promoting the combustion of hydrocarbons and oxidation of other noxious gases under the high temperature conditions prevalent in an exhaust mufiler. Accordingly, the exhaust gases are partially purified in their passage through the exhaust conduit and these hot partially purified exhaust gases are further purified in mixing chamber 16 where they are admixed with the super-heated air discharged as a jet from conduit 17 prior to discharge through outlet 14.

The housing of a rnuflier according to the present invention for a standard passenger automobile is typically about 17 inches long by about 6 inches wide by about 4 inches high. The air and exhaust conduits are desirably formed from extruded square 2 inch stainless steel tubing. The exhaust conduits are about 12 inches in length and the inlet and mixing chambers are each about 2 inches in depth. The exhaust conduits are desirably filled with wire coils throughout their entire length. Baflle plates 18 and 19 are desirably spaced about 2 inches apart.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A pollution reducing mufiler for an internal combustion engine comprising:

(A) an elongated tubular housing of heat resistant metal, having end walls at opposite ends,

(B) a reduced diameter exhaust gas inlet through the wall at one end of the housing, and a reduced diameter purified gas discharge through the wall at the opposite end of the housing,

(C) an exhaust receiving and distributing chamber within the housing adjacent the inlet end and an air and exhaust mixing chamber within the housing adjacent the discharge end,

(D) an open-ended elongated air conduit extending from exterior of the inlet end wall through said housing to said mixing chamber,

(E) a plurality of open-ended elongated exhaust conduits extending from said receiving chamber to said mixing chamber, and

(F) a plurality of coils of stainless steel wire disposed in series in each of said exhaust conduits, said coils of wire being disposed with their axes extending transversely relative to the longitudinal axes of the exhaust conduits.

2. A mufiier according to claim 1 further characterized in that a plurality of spaced apart baflie plates are disposed within said air conduit extending alternately from opposite sides of said conduit to define a serpentine air flow path through said conduit.

3. A mufller according to claim 2 further characterized in that said bafiie plates are generally parallel to each other and the alternating plates extend angularly inwardly from the sides of the conduit toward the opposite sides thereof in the downstream direction.

4. A muffler according to claim 1 further characterized in that said air and exhaust conduits are formed from stainless steel tubing of rectangular cross section disposed in side-by-side abutting relation.

5. A mufiler according to claim 4 further characterized in that said coils of stainless steel wire are of a diameter and length corresponding generally to the inside cross sectional dimensions of said exhaust conduits, whereby substantially all of the exhaust flow through said conduits is transversely through said coils.

6. A mufiier according to claim 1 further characterized in that the open ends of said exhaust conduits are closed by and adjacent wire coils within said conduits are separated by rigid coarse mesh stainless steel screening.

7. A mufiler according to claim 4 further characterized in that:

(A) said mufiler housing is generally oval in cross section,

(B) the combined height and width of said abutting rectangular conduits conform generally to the inside dimensions of said housing,

(C) transverse baffies obstructing at least some of the longitudinal passages between the inside housing walls and outside conduit walls, and

(D) openings in the exhaust conduit walls adjacent to and upstream from said bafiies.

8. A muflier according to claim 1 further characterized in that:

(A) said air and exhaust conduits are formed from stainless steel tubing of rectangular cross section disposed in side-by-side abutting relation,

(B) a plurality of spaced apart parallel bafiie plate are disposed within said air conduit extending alternately from opposite side walls of said conduit angularly inwardly in the downstream direction,

(C) said coils of stainless steel wire are of a diameter and length correspondnig generally to the inside cross-sectional dimensions of said exhaust conduits, and

(D) the open ends of said exhaust conduits are closed by and adjacent wire coils within said conduits are separated by rigid coarse mesh stainless steel screenmg.

References Cited UNITED STATES PATENTS 1,828,318 10/1931 Clark 23-288 R 2,501,767 3/1950 Fluor et al 181-51 2,947,600 8/1960 Clayton 23-288 F 3,017,255 1/1962 Norris 181-36 C 3,109,715 11/1963 Johnson et al. 181-36 C 3,592,613 7/1971 Boyd 23-288 R 3,611,714 10/1971 Bjork 181-43 ROBERT S. WARD, ]R., Primary Examiner US. Cl. X.R. 

